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Sanyo DP58D34 LED TV - No picture, but sound and green light    
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Tom-in-KY



Joined: 28 Apr 2016
Posts: 7
Location: Bluegrass State

PostPosted: Thu Apr 28, 2016 2:37 pm    Post subject: Sanyo DP58D34 LED TV - No picture, but sound and green light Reply with quote

I have a Sanyo 58" LED TV (DP58D34) that is a little over a year old. Last week the picture suddenly went black. Still see the green indicator light, and audio still works. When you first turn it on and it goes through its power up routine, you see a very brief flash on the screen for about a half second, then it goes black. I have read up a little bit, and it sounds like it may be an issue with the main power board or the LED driver. I looked closely at all of the electrical boards in the TV and did not see any telltale swollen capacitors or other obvious damage.

Can someone point me in a direction to diagnose which board is likely to be bad? I have found both the main power board and the LED driver board for sale as take-outs from sets with broken screens, but I don't know which one to buy. I have also read that sometimes the problem can be with one of more LED's being burnt out, but I wouldn't expect to see the flash on the screen if that was the case. Am I correct in my assumption?

Looking forward to any help you can provide. Thanks!
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JTS1957



Joined: 21 Jan 2009
Posts: 2247
Location: Far, Far Away

PostPosted: Thu Apr 28, 2016 4:34 pm    Post subject: Reply with quote

Tom-in-KY wrote:
Am I correct in my assumption?
No.

One in a string of series wired LEDs may light for an instant, get hot and open internally. Or if sets of boards plug together, may develop a bad connection where they join one another.

Hold a flashlight near the LCD screen and see if you can see a picture, menus, etc. If you see video, then you know its either the LED driver or LED back light bulb(s).
Tom-in-KY



Joined: 28 Apr 2016
Posts: 7
Location: Bluegrass State

PostPosted: Thu Apr 28, 2016 10:42 pm    Post subject: Reply with quote

JTS, I forgot to mention that I did the flashlight test, and the image is there, so I have some type of backlight problem.

I was really hoping this would be a simple board replacement, but I am starting to think that I have one or more bad LED's. Not looking forward to having to totally disassemble the screen. This guy's YouTube video pretty much describes what my set is doing, and he had to replace LED's

https://www.youtube.com/watch?v=Bf5T2wwtydY

Is there any sure way to rule out the LED's before I disassemble it?
Tom-in-KY



Joined: 28 Apr 2016
Posts: 7
Location: Bluegrass State

PostPosted: Fri Apr 29, 2016 5:28 am    Post subject: ... and it keeps getting worse! Reply with quote

I am having no luck at all finding any replacement LED strips for ANY Sanyo TV, much less my model. Can anyone point me to a source? You would think there would be a good aftermarket source for these.

Is it possible to replace just the individual LED's like the guy did in the video? I realize the strips are specific to the individual make and model, but are the LED's themselves fairly interchangeable? This is looking more and more like my almost TV is going to become fodder for the landfill! Mad
Tom-in-KY



Joined: 28 Apr 2016
Posts: 7
Location: Bluegrass State

PostPosted: Fri Apr 29, 2016 6:00 am    Post subject: Reply with quote

OK, found a video where someone was replacing individual LED's by simply cutting portions of a donor LED strip and gluing them onto the damaged LED strip, then soldering jumper wires. Wondering if this might be a better way to go for those of us who do not solder professionally.

Either that, or I might try to find a local repair shop who can do the soldering for me. My main question at this point concerns compatibility of the individual LED's. Do they have pretty much the same rating?
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Tom-in-KY



Joined: 28 Apr 2016
Posts: 7
Location: Bluegrass State

PostPosted: Fri Apr 29, 2016 6:05 am    Post subject: Reply with quote

The more reading I do about LED TV's, the more I wish I had known about the high failure rate before I bought the darned thing. I would have probably looked for an LCD instead. From what I have seen / read so far, it appears that the LED failures are pretty common. Sounds like turning down the backlight will help them last, but they are all doomed to failure eventually. Sure would be nice if the manufacturers made it easy and simple to replace the defective LED's. They could have made the front panel of the TV easily removable, and then make it so that the LED's just pop out of a socket. Might keep some of these out of the landfill. I for one would be happy to spend an extra $50 - $75 or more for a TV that is easily serviceable down the road. Of course, some other electrical component will probably crap out instead!
JTS1957



Joined: 21 Jan 2009
Posts: 2247
Location: Far, Far Away

PostPosted: Fri Apr 29, 2016 7:07 am    Post subject: Reply with quote

http://www.cnet.com/news/led-lcd-backlights-explained/
Tom-in-KY



Joined: 28 Apr 2016
Posts: 7
Location: Bluegrass State

PostPosted: Mon May 02, 2016 8:32 am    Post subject: Reply with quote

Found out that the AMEX card I used for my purchase will double my factory warranty, so I might be in luck! I'm going to see if the repair shop can replace ALL of the LED strips in the backlight if that turns out to be the issue. That way I might end up with some spares in case this happens down the road.
kuhurdler



Joined: 28 Dec 2006
Posts: 2846
Location: Overland Park, KS

PostPosted: Tue May 03, 2016 3:10 pm    Post subject: Reply with quote

I've done just the method you spoke of when I removed an LED from a donor TV, and soldered it in place on the LED strips. It works, but it was far more effort than I expected. I used a hot air gun to remove the old LED, and resolder the new one.
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